This invention relates generally to a customer replaceable unit (CRU) for a printing machine, and more particularly concerns a xerographic module for an electrophotographic printing machine.
In a typical electrophotographic printing process, a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charges thereon in the irradiated areas. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules to the latent image forming a toner powder image on the photoconductive member. The toner powder image is then transferred from the photoconductive member to a copy sheet. The toner particles are heated to permanently affix the powder image to the copy sheet.
In printing machines such as those described above, a CRU is a customer replaceable unit which can be replaced by a customer at the end of life or at the premature failure of one or more of the xerographic components. The CRU concept integrates various subsystems whose useful lives are predetermined to be generally the same length. The service replacement interval of the CRU insures maximum reliability and greatly minimizes unscheduled maintenance service calls. Utilization of such a strategy, allows customers to participate in the maintenance and service of their copiers/printers. CRUs insure maximum up time of copiers and minimize downtime and service cost due to end of life or premature failures.
It is desirable to have a CRU that enables a variety of machine subsystems to be incorporated into a single unit while maximizing the useful life of each component. It is further desirable to utilize a CRU that allows service to a machine to be performed efficiently and at a relatively low cost and in some cases to be serviced by the user himself. It is a further benefit to have the ability to reuse and recycle various CRU components in today's climate of environmental awareness.
It is important that customer replaceable units be customer friendly. In other words, it is important that the CRUs may be easily removed and reinstalled with minimal instructions and minimal training. Unfortunately, the CRUs typically include a number of items that are critical to the proper operation of the machine, e.g. charging devices, photoreceptors and developer subsystems. These components and subsystems are very delicate and need to be properly handled and to not be damaged during the installation and removal of the CRUs. CRUs, particularly xerographic CRUs, typically include toner, e.g. waste toner or new toner. Access must be had between a waste toner reclaim bottle and the cleaning portion of the xerographic CRU. During removal and transportation of a CRU, it is important that the toner stored within a toner supply source or a toner waste bottle be properly secured. Waste toner bottles as well as new toner bottles typically include seals and/or covers to prevent the inadvertent spilling of toner into the CRU. The customer must properly position such seals or doors during CRU installation and removal.
The cleaning or removal of excess toner from the photoconductive member in a printing machine is typically handled by a cleaning blade. The photoconductive member is typically very delicate and may easily be damaged by the cleaning blade. CRUs that must be separated from a photoconductor during assembly and removal require that the cleaning blade be moved in a position away from the CRU prior to removal of the CRU. The critical alignment and positioning of components within a CRU for the respectively removal and installation of the CRU make the CRU installation and removal process difficult for an untrained customer.
Electrophotographic printing and copying machines are very susceptible to airborne contamination within the printing machine. For example, airborne contamination may damage intricate electronic components, i.e. the charge corotron and other corotrons within the printing machine, interfere with the quality of the copy in the exposure and development station and generally cause copy quality and reliability problems within the printing machine. These problems are exacerbated by the cleaning of the photoconductive surface which must be performed as part of the xerographic process. The cleaning of the photoconductive surface may cause components, in particular marking particles in the form of toner, to become airborne within the printing machine.
Attempts have been made to remove the airborne dust or toner within the internal portion of the printing machine. For example, air permeable filters have been used in conjunction with motor driven fans and conduits to positively direct a flow of air within the printing machine through a filter media so that the contamination may be trapped within the filter. In order to permit the passage of air through the filter, the filter media is made of a lightweight weak material which usually can not adequately support itself.
The internal portion of the filter into which the flow of air is directed has a tendency to collapse or to not be fully open thereby decreasing the effectiveness of the filter. A support structure may be positioned within the filter opening to assure that the filter is adequately opened and in proper orientation to provide for effective air flow. This inner structure reduces the exposed area of the filter reducing its efficiency. Further, this internal structure may add cost to the filter and make recycling of the filter media more complicated.
The filter after collecting sufficient airborne toner may become clogged. The clogged filter may require replacement. The filter may be separately replaced or as has become more recent practice, be combined with other customer replaceable components into a customer replacement unit or CRU which has a scheduled regular replacement period to assure maximum efficient machine utilization.
The following disclosures may relate to various aspects of the present invention.
U.S. Pat. No. 5,612,768
Patentee: Kim PA1 Issue Date: Mar. 18, 1997 PA1 Patentee: Reddy et al. PA1 Issue Date: Oct. 22, 1996 PA1 Patentee: Meguro et al. PA1 Issue Date: Sep. 17, 1996 PA1 Patentee: Hobson et al. PA1 Issue Date: Jun. 18, 1996 PA1 Patentee: Park PA1 Issue Date: Jan. 10, 1995 PA1 Patentee: Kerr et al. PA1 Issue Date: Dec. 14, 1993 PA1 Patentee: Haupt et al. PA1 Issue Date: Dec. 8, 1992 PA1 Patentee: Tonomoto PA1 Issue Date: Jun. 4, 1991 PA1 Patentee: Tonomoto PA1 Issue Date: Jul. 3, 1990
U.S. Pat. No. 5,568,230
U.S. Pat. No. 5,557,386
U.S. Pat. No. 5,527,569
U.S. Pat. No. 5,379,506
U.S. Pat. No. 5,270,731
U.S. Pat. No. 5,170,211
U.S. Pat.No. 5,021,831
U.S. Pat. No. 4,938,786
Some portions of the foregoing disclosures may be briefly summarized as follows:
U.S. Pat. No. 5,612,768 discloses an image forming apparatus having an air flow structure capable of generating an airflow along a direction substantially perpendicular to a photosensitive drum through a charging device in order to prevent contamination of a corona wire (i.e., discharge wire). The image forming apparatus constructed according to the principles of the present invention includes a main frame having parallel side walls with a side wall having an air intake port. A cover is pivotally connected at one end of said main frame so as to allow closing and opening of the image forming apparatus and an image carrier is installed in the main frame so as to form a latent image. A ventilation fan installed at the port in the side wall generates an air flow through an air duct installed to guide the air flow. A charging device positioned in parallel with the image carrier when the cover is closed so as to charge a surface of the image carrier for forming the latent image, includes a corona wire extending in a direction of the image carrier for performing charging operation in response to application of a voltage, and a shield case for protecting the corona wire and having at least one opening receiving air flowing from the duct and allowing the air to flow through the corona wire so as to prevent contamination of the wire.
U.S. Pat. No. 5,568,230 discloses a corona generator including a support structure and an electrode mounted on the support structure is provided. The corona generator also includes an ozone neutralizing element removably mounted on the support structure proximate to the electrode. The ozone neutralizing element has various substrates and types for removably mounting the element.
U.S. Pat. No. 5,557,386 discloses a toner recovering device for an electrophotographic apparatus, which includes: a dust collector connected to a device for cleaning untransferred toner remaining on a photosensitive body; a toner recovering filter having an inlet port for introducing an air-toner mixture from the dust collector side and an exhaust port for filtering the air-toner mixture and discharging the air from which the toner has been removed; a filter mounting section for mounting the toner recovering filter; a joint mechanism having a joint and a hose member, one end of the hose member capable of being connected to the dust collector and other end thereof being joint, the joint being disposed at the inlet port, the joint mechanism being arranged in the filter mounting section in such a manner as to be opened and closed; a detector for sensing that the toner recovering filter has been mounted or not onto the filter mounting section; and a pulling member for coupling the inlet port of the toner recovering filter to the joint in synchronism with an operation of mounting the toner recovering filter onto the filter mounting section.
U.S. Pat. No. 5,527,569 discloses an improved electrically conductive filter media particularly suitable for use in applications where static electricity must be dissipated. The filter media of the present invention comprises a microporous filtration layer having electrically conductive particles embedded therein. When attached to support media, this structure provides exceptional filtration efficiency while assuring a consistent and evenly distributed electrical pathway to ground.
U.S. Pat. No. 5,379,506 discloses a process and device enabling easy and reliable placement of an ozone filter from and into a frame member of an electrophotographic apparatus. The device uses a pair of slots formed on both sides of a filter mounting recess and a filter holder which includes, as a unit, a portion provided with the ozone filter, a pair of tension members with raised edges for engaging with the pair of slots to affix the filter holder within the filter mounting recess when the filter holder is inserted into the filter mounting recess, and grip members for handling the filter holder. Grip members, when pressed towards each other, produce a tension and allow the filter holder to be quickly and easily removed from or inserted into the filter mounting recess.
U.S. Pat. No. 5,270,731 discloses an imaging system comprising a source of light movable with respect to a writing element and projectable thereon to generate an image, a focusing system is provided for focusing a light source which generates a first beam of light of a wavelength selected to be actinic with respect to the writing element. At least a portion of the first beam of light is absorbed by the writing element. The apparatus comprises a material feeder to automatically supply donor sheets and receiver sheets independently to a writing platen or drum, and to selectively load and unload the donor sheets from superposition with the receiver sheet without disturbing the registration of the receiver sheet. Also included are components which contribute to the quality of the images generated, such as relatively inexpensive, low jitter transports and drives for the writing head and imaging drum. In particular, the positive air flow through the apparatus is carefully directed to prevent contamination of the image by air-borne dirt.
U.S. Pat. No. 5,170,211 discloses a copying apparatus which includes a filtering system defining an inlet and an outlet to the corotron cavity. Both the inlet and the outlet include filter material for filtering the air before it is delivered to the corotron cavity and filtering effluents generated during actuation of scorotron wires. The pathways to the inlet and the scorotron cavity are sealed to ensure little or no leakage of contaminated air which could be exposed to the scorotron wires. For this purpose two activated charcoal filters are doped with silver on a foam substrate, utilized both for the inlet and the outlet filters.
U.S. Pat. No. 5,021,831 discloses an electrophotographic/electrostatic recording apparatus especially for high speed recording, a toner image on a recording sheet is fused thereon by a flash lamp in a fixing unit, and smoke is generated thereby. Smoke and toner dust in the ambient air should be removed before it is exhausted out of the apparatus by drawing the air through an air filter. The invention discloses that is it effective to use an air filter structure comprising a plurality of filter units, wherein a first filter unit made of electrostatically charged fibrous material is utilized at the inlet side of the air filter. The first filter unit has a comparatively greater porosity and attracts and removes toner particles charged with the opposite polarity to that of the electrostatically charged fibrous material. Therefore, the air, a substantial part of toner dust being removed therefrom, can more easily enter into the following filter units for removal of smoke, resulting in increased endurance of the air filter.
U.S. Pat. No. 4,938,786 discloses an air filter structure is described including a plurality of filter units, wherein a first filter unit made of electrostatically charged fibrous material is utilized at the inlet side of the air filter. The first filter unit has a comparatively greater porosity than the remaining filter units and attracts and removes toner particles charged with an opposite polarity to that of electrostatically charged fibrous material in the first filter unit. Therefore, the air, with a substantial part of toner dust removed, can more easily enter into the remaining filter units for removal of smoke, resulting in increased useful life of the air filter.